Freddie Woodman made three penalty saves as Aberdeen beat Kilmarnock in a shootout to set up a Scottish Cup semi-final against Motherwell.

Stephen O'Donnell struck to put Killie ahead in extra-time.

But Kenny McLean quickly levelled from the penalty spot after Stevie May had been fouled.

Though Niall McGinn was unsuccessful for the Dons in the shoot-out, ex-Killie keeper Woodman denied Eamonn Brophy, Greg Taylor and Greg Kiltie.

Rugby Park was rocking at kick-off with a sizeable, expectant home crowd roaring on the home side.

It quickly became apparent that this one might go the distance and it duly did. The importance of the occasion seemed to nullify both sides as it appeared no-one wanted to lose.

McLean came closest to an opener for the visitors in the first half with a fizzing drive the that flew past Jamie MacDonald's post.

Rory McKenzie did create some excitement and a melee when he seemed a touch too aggressive on Gary Mackay-Steven, who was grounded.

McKenzie was booked and may have been fortunate not to earn another yellow card when he later drove at the Aberdeen defence and went down.

McLean was booked for that challenge but it was not clear if he connected at all with the Kilmarnock midfielder.

The Dons midfielder would have known he would miss the semi-final as a result through suspension if Aberdeen progressed. Despite that, he proved influential.

Jordan Jones fired the first shot on target after over an hour, which Woodman dealt with comfortably.

Shay Logan then saw his hopes of a semi-final place evaporate when he impeded Jones and was cautioned. His night would get worse later.

O'Donnell was close with a thumping left-foot drive that tested Woodman and the full-back tried again with a net-bound shot which blocked by Scott McKenna's fine intervention, the defender having just been called up to the Scotland squad.

At the other end, Ryan Christie hit the wall with a free-kick but smashed the rebound narrowly past with MacDonald looking beaten.

In the final seconds of regulation time, substitute Brophy set up Alan Power, who side-footed well wide. It was representative of a poor contest overall.

But things changed in extra-time.

Kilmarnock cleared a corner and Brophy outmuscled Shay Logan all too easily. O'Donnell then appeared from nowhere all alone in the box to slam home Brophy's square ball.

However, moments later Kirk Broadfoot impeded May as he was about to shoot and McLean's finish from 12 yards was emphatic.

Moments later, the midfielder struck a wonderful shot which cannoned off the crossbar.

There was more drama to follow. Brophy connected with a header which found the net but his delight was cut short by an offside flag.

McLean tried again with a shot which crept agonisingly past.

Graeme Shinnie was booked late on and became the third Aberdeen player who would miss the semi-final if the Dons got there.

Chidi Nwakali then produced a wonderful late shot as impressive as MacDonald's save which kept Kilmarnock in the cup and led to the shootout.

And Woodman became the hero - superbly saving from Brophy, keeping out Taylor's weak effort and sealing victory with another save from Kiltie, all of which rendered McGinn's effort off the bar redundant.